Tidal Terms in Universal Time: Effects of Zonal Winds and Mantle Q.

Abstract

The zonal response coefficient kappa is studied, and some improvements in its determination are made. First, the reprocessing of the Bureau International de l'Heure data with the 1980 International Astronomical Union nutation series is found to result in improved estimates of kappa . Second, a time series of the angular momentum of the atmosphere is found to have power in the tidal bands, and it is demonstrated that removing the atmospheric influence from the rotation data leads to better estimates of kappa . The frequency dependence of kappa due to finite dissipation in the earth is computed, and the observations are subsequently shown to limit the allowable models of dissipation. Finally, dynamic ocean tide models are studied, and it is concluded that the rotation data cannot distinguish between these and an equilibrium tide.